| 摘要 |
PURPOSE:To decrease the number of parts of the power amplifier part of the acoustic reproducing device which builds in a head phone jack and speaker by grounding commonly for the speaker and installing a voice coil connecting prescribedly other respective ends to the output side of the power amplifying part at the right and left channel sides. CONSTITUTION:One end of voice coils 12 and 13 of a speaker 11 is respectively grounded commonly, and other end is connected through two internal switches of a head phone jack 10 with the output side of right and left power amplifying parts. When a head phone plug is inserted to the jack 10, a switch 7 is interlocked, and the right and left channel signals are independently amplified with amplifiers 3 and 4, etc., and supplied to the head phone. On the other hand, when the head phone plug is removed, the right and left channel signals are mixed through the switch 7, supplied to the coils 12 and 13 and the sufficient sound is outputted. Thus, BTL connection using plural complicated switches becomes unnecessary, and the number of parts of the power amplifier part of the acoustic reproducing device which builds in the head phone jack and the speaker. |
